HELP! Diatomaceous Earth doesn't seem to be working on fleas

jplee3November 8, 2012

Hey guys,

I'm wondering what's going on here - I purchased some DE on Ebay back in August and started applying it around the yard. I would continue to walk out there and still found fleas out there though. I ended up buying nematodes and applying them earlier this week (hopefully it's more effective).

Anyway, I decided to do a little experiment and caught some fleas and put them in a jar with several tablespoons of DE. One of the fleas died but I think it was because the jar was slightly wet and I put DE in after and it probably drowned in some of the paste that formed. I made sure to put more fresh DE in after the water dried up too.

I still have 3 fleas left (one I caught a couple days ago but the other two have been in the jar for a good week now). The DE seems to be having no effect on them!

I've read conflicting information from various sources - some say DE doesn't work on adult fleas and only works on larvae. Others have reported their experience that it does work and have even said they caught fleas, put them in a jar with DE, and they were dead within hours at most.

Horticultural and food grade Diamotaceous Earth are the same thing while pool grade is different. DE is a very passive insect control and may well take quite some time to control any target insect because they must make contact with it.

Thanks for the information. I checked yesterday after work and actually found that only two fleas are alive now - I think one went down, unless I was just having a hard time seeing. I also noticed that they seem like they're "shivering" while crawling around. I'm wondering if this is the slow effects of the DE on their body. In any case, it seems like in a controlled environment it may take 5-7 days for the DE to actually kill off the fleas. I'm wondering how effective sprinkling the DE around my yard has really been for that matter. I have doubts in my application of it - I can see how it would work well for covering small cracks and putting at baseboards, but not for a broad application such as in a yard.

What about mixing the DE into the existing soil though? Or would that disperse the particles too much for them to even be effective?